Method and apparatus for open end spinning



Sept. 23, 1969 c. B. CRANDALL ETAL 3,463,116

METHOD AND APPARATUS FOR OPEN END SPINNING 5 Sheets-Sheet 1 Filed Feb. 26, 1968 a 5g w w 5 l 5 I 5M m3 lw Z #6 5 R05 Y mm im maww; VFT T m 1, 5 A H mm W n p 3, 1969 c. a. CRANDALL ETAL 3,468,116

METHOD AND APPARATUS FOR OPEN END SPINNING Filed Feb. 26, 1968 5 Sheets-Sheet 2 IN\/ENTOR5 Char/e5 13 Cram/a Fr n/fl/rl L TBa/MZind ar 5 flaw M ATTORNEYS Sept. 23, 1969 c. a. CRANDALL ETAL 3,468,116

METHOD AND APPARATUS FOR OPEN END SPINNING Filed Feb. 26, 1968 5 Sheets-Sheet 3 mvsmons Charles 5 Crandal/ Frzn/(l/n L. own end a ly I d- M AT TORNEYS Sept. 23, 1969 c. a. CRANDALL ETAL 3,468,116

METHOD AND APPARATUS FOR OPEN END SPINNING Filed Feb. 26, 1968 5 Sheets-Sheet 4 INVENTORS Char/es B. Own/all ATTORNEYS Sept. 23, 1969 c. B. CRANDALL ETAL 3,468,116

METHOD AND APPARATUS FOR OPEN END SPINNING Filed Feb. 26, 1968 5 Sheets-Sheet 5 INVENTORS Char/es B. Cranaal/ AT TORNEYS United States Patent 3,468,116 METHOD AND APPARATUS FOR OPEN END SPINNING Charles B. Crandall and Franklin L. Townsend, Rockford,

Ill., assignors to Barber-Colman Company, Rockford,

Ill., a corporation of Illinois Filed Feb. 26, 1968, Ser. No. 708,145 Int. Cl. D01d 7/00 US. Cl. 5758.89 24 Claims ABSTRACT OF THE DISCLOSURE different speed and bears against the band of fibers to.

define the point at which the band is drawn away from the wall and led inwardly at a substantial angle and then out of the chamber through an axially extending tube by the action of take-up rolls. The latter hold the advancing band of fibers against turning so that the length of the traveling band between the nipping element and the rolls is twisted uniformly in the rotation of the perforated wall and the nipping element.

Background of the invention It has long been known that the high cost of doffing and subsequent handling of bobbins of yarn spun by the conventional ring method can be eliminated by the socalled open-end or break-type spinning. Although machines are now available for practicing this method using conventional roving or sliver as a source of fibers, no yarn produced on a commercial basis by open-end spinning has found wide acceptance by the textile industry.

One type of open-end spinning involves feeding detached fibers into an annular chamber defined by a perforated outer wall and rotated at high speed, the fibers becoming distributed by centrifugal force around the wall and build up on the wall in the form of a band. One end of the latter is drawn inwardly and continuously away from the wall and along the axis thereof through take-up rolls which hold the band against turning. As a result, the length of the band between the wall and the rolls is twisted and converted into yarn which, beyond the rolls, is wound into a suitable package.

Summary of the invention The primary objective of the present invention is to improve upon and overcome the deficiencies of open-end spinning as practiced heretofore and produce yarn of a quality comparable to that obtainable by conventional ring type spinning, and this while employing spinning units capable of being arranged and operablein multiple along a frame and comparable to ring type spinning units in initial cost and cost of operation.

These objectives are achieved by delivering into one end of an annular chamber having an outer perforated wall 11 rotating at high speed, a continuous stream 12 of detached fibers which, under centrifugal force and suction are turned outwardly and become parallelized and distributed around the wall so as to build up thereon in the form of a band 13 (FIGS. 4. 7. 8 and 11) of sufiicient 3,468,116 Patented Sept. 23, 1969 fiber density to be twisted into yarn. In a unique and rather unexpected manner, the fibers of the band pass between the wall and a nipping element 14 which revolves around the axis of the wall in precise synchronism therewith and at a small fraction of the wall speed and accurately controls the point at which the band 13 is drawn inwardly away from the wall and pulled along the drum axis at a uniform rate by take-up rolls 15 which hold the band of fibers against turning so that the rotation of the wall and nipping element imparts an accurately controlled amount of twist to each length of the hand drawn out of thecharnber 10 and past the rolls.

The invention also resides in the novel construction of the nipping element for engaging the fiber band under light and accurately controlled pressure so as to insure that the fibers continuously supplied into the open end of the collecting chamber 10 come between the nipping element and the perforated wall 11 thereof and become properly parallelized in forming the band 13 of uniform density before being drawn away from the wall at the trailing side of the nipping element in its motion relative to the wall.

A further object is to improve the uniformity and strength of the final yarn by driving the take-up rolls at a peripheral speed slightly greater than the linear speed of the fiber hand drawn inwardly from the nipping element so as to effect a small amount of drafting of the fibers of the hand during the twisting thereof.

Another object is to provide a novel method of starting the spinning in a unit of the above character and involving the extension of a toool into the collecting. chamber through the outlet end of the spinning head.

The invention also contemplates a novel construction of and drive for the improved spinning unit to permit similar units to be arranged side by side in closely spaced and compact relation along a common frame and all of the rotary parts thereof driven in synchronism from common shafts on the frame.

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Brief description of the drawings FIGURE 1 is a fragmentary and schematic perspective view of part of a spinning frame having spinning units embodying the novel features of the present invention.

FIG. 2 is a fragmentary broken-away perspective of a part of one of the spinning units shown in FIG. 1.

FIG. 3 is a perspective view of part of the twisting head.

FIG. 4 is a fragmentary section taken along the line 44 of FIG. 2.

FIG. 5 is a fragmentary section taken along the line 5-5 of FIG. 4.

FIG. 6 is a perspective view of the nipping element.

FIG. 7 is a perspective view showing the shape taken by the fibers in the course of the spinning.

FIG. 8 is a view of part of FIG. 4 illustrating one step for starting the spinning.

FIG. 9 is a fragmentary perspective view of the fishing tool shown in FIG. 8.

FIG. 10 is a diagrammatic view showing the drive for different parts of a spinning unit.

FIGS. 11, 12. and 13 are views similar to FIG. 5 showing different steps in the spinning.

Description of the preferred embodiment Spinning units 16 of the construction shown in the drawings for purposes of illustration may be utilized to advantage in practicing the improved spinning process as summarized above. As shown in FIG. 1, the units may be arranged side by side along a frame 17 the same as in conventional ring spinning and driven from a common shaft 18 (FIG. 10) spanning gear housings 19 and driven by a motor 20 from which other parts of the spinning -units are driven at proper speeds and in precise synchronism through suitable sets of gears shown schematically in FIG. 10.

Herein, the fiber collecting or perforated wall 11 takes the form of a cylindrical drum 21 (FIG. 4) of short axial length seated in a groove 22 around the lip 23 of a generally cylindrical cup-like body 24 whose centrally apertured bottom 25 rests on a thrust washer 26 and is attached onto the end of a shaft 27 journaled in anti-friction bearings 28. The latter are vertically spaced in the present instance and supported in a horizontal cross-member 29 of the frame. The drive to each shaft 27 extends from the main drive shaft 18 through suitable gearing 30 (FIGS. 1 and 10) and a toothed belt 31 to a pulley 32 on the lower end of the shaft.

The drum 21 is clamped against the cup lip by a cover in the form of a flat ring 33 secured to the cup by screws 34 and having an inner frusto-conical wall 35 which diverges at about 45 degrees from a large center opening 36 to the perforated wall 11 or inner surface of the drum. Around its full circumference and substantially its full depth, the drum is perforated by closely spaced holes 37 which herein are arranged in three vertically spaced rows with the holes of adjacent rows staggered relative to each other. Preferably the holes are about .080 of an inch apart and .040 of an inch in diameter.

The stream 12 of fibers may be derived from any suitable source such as a sliver drawn from the usual storage can or, as in the present instance, from the roving 39 used in conventional spinning. The roving is drawn off from one or more bobbins 40 by feed rolls 41 driven at proper speeds through suitable gearing 18 (FIG. 10) and from the main shaft 18 and arranged above the usual trumpet 44. Longitudinal shifting of the roving fibers relative to each other to form the stream 12 of loose fibers may be achieved by a conventional drafting device including upper and lower rolls 42 and 43 and belts 45 and 46 engaging opposite sides of the advancing roving and driven at different speeds through shafts 47 and in proper synchronism with the feed rolls. The spinning unit is mounted on the frame with the cover ring 33 disposed quite close to and offset transaxially from the lower drafting rolls 43 so that the stream 12 of drafted fibers is delivered substantially parallel to the drum axis and into the end of the collecting chamber through the cover opening 36 quite close to the periphery thereof as shown in FIGS. 1, 2 and 4.

To separate and detach the loose fibers from each other and draw the same rapidly against and collect them on the perforated wall 11 to form the band 13, the invention contemplates drawing air at relatively high velocity first along the drum axis into the cover opening 36 and then outwardly through the drum perforations 37 over an arc thereof which extends from a point opposite the incoming fiber stream a short distance around the drum 21 in the direction of rotation thereof. For this purpose, a groove 50 between the outer peripheries of the cover ring and the cup lip is surrounded closely over this are by the end 51 of a nozzle 52 (FIGS. 1, 4 and 11) flaring from a branch 53 communicating with a suitable power driven vacuum pump 54.

It will be observed that the drafted fibers passing the lower rolls 43 enter the rapidly moving air stream along a path extending generally parallel to the axis of the perforated wall 11 spaced inwardly from this wall a distance determined by the radial width of this wall. The fibers of the stream are further separated and detached from each other and turned outwardly against the diverging surface 35 by which they are guided into the collecting chamber 10 and directly onto the perforated wall 11 under the force of the air current being drawn outwardly through the perforations 37. The outward turning of the fibers controlled by the inclination of the wall 35 thus is more or less gradual so as to assist in assembling the fibers on the wall 11 in relatively parallel relation. Also, the fibers when contacting the wall 35, become subjected to centrifugal force which assists in directing the fibers to and holding the same against the wall 11 including the areas not exposed to the suction nozzle. Thus, in a multiplicity of revolutions of the drum 21, the fibers build up around the surface 11 to form the band 13 (FIGS. 5 and 7) which is relatively fiat and about as wide as the perforated area of the collecting surface. The fiber density of the band as it passes under the nipping element 14 to be described later is substantially uniform apparently due to the tendency of the fibers entering the collecting chamber as the band builds to be drawn to those passing areas of the perforated wall which are subjected to the greatest suction.

The band of fibers thus accumulated is broken and drawn progressively off from the perforated wall first inwardly away from the wall 11 and then out of the collecting chamber along the axis thereof in a manner to utilize the rotation of the drum 21 and the nipping element 14 to impart the desired twist to the fiber band as it travels out of the collecting chamber and along the drum axis. This force for pulling the band along this axis is applied by the take-up rolls 15 which are spaced axially a substantial distance from the outlet end of the collecting chamber and serving to hold the band of passing fibers against turning. One of the take-up rolls of each of the spinning units is driven at a predetermined selected speed from the power unit 20 and through gearing 55 (FIG. 10).

After being twisted to the desired degree, the final yarn 56 leaving the take-up rolls 15 passes around spaced rolls 57 and an intermediate dancer roll 58 loaded by a spring 59 and then over a helically grooved drum 61 by which the yarn is traversed back and forth as it is wound onto a core 62 to form a package 63. The core and package are carried by an arm 64 and held by a spring 65 against the drum which is also driven in synchronism with the take-up rolls.

The present invention contemplates a novel construction of the nipping element 14 above referred to so as to contact the built up fiber band 13 under predetermined light pressure across the full width of the band and control positively the progress of the element around the drum axis and therefore the point at which the fiber band is drawn inwardly and away from the perforated wall 11. Also, the construction is such as to insure proper restarting of the band formation around the wall after the nipping element passes and also proper entry of all of the band of fibers between the wall and the active surface of the element. To these ends, the nipping element whose construction will be detailed presently is mounted on a head 65 (FIGS. 2, 3 and 4) disposed Within the cup 24 and pressed intermediate its ends into a shouldered bushing 66 which is journaled in anti-friction bearings 67 supported by the cup. The escape of fibers to the bearings from the collecting chamber 10 is prevented by a seal ring 68 between the cup and the head. Herein, the head is a solid cylinder secured to a bottom plate 69 which rests on a thrust bearing 71 and is fast on the upper end of a tubular shaft 72 which is concentric with and projects through the tubular drum shaft 27 and at its lower end is journaled in bearing 73 (FIG. 2) supported by the frame 29. A pulley 74 fast on the shaft 72 meshes with a toothed belt 75 driven from the main drive shaft 18 through suitable gearing 76 (FIG. 10) and at a predetermined speed synchronized as later described with the speed of the perforated wall 11.

The edge of the opening at the upper end of the shaft '72 is rounded as shown at 77 (FIGS. 4 and ll) at a suitable radius to permit the twist produced in the fiber band between the surface 77 and the take-up rolls 15 to travel past the surface 77 toward the nipping element 14, thus insuring sufficient twist between the surface 77 and nipping element to prevent the band from pulling apart. The

opening at the shaft end as defined by the rounded surface 77 communicates with a radially disposed and outwardly opening slot 78 (FIGS. 3 and 4) disposed between the surface and the plane of the perforated drum 21 and having, for a purpose to appear later, an inner wall 79 inclined relative to the drum axis and extending to the collecting chamber from a point 81 on the rounded end surface 77 on the side thereof opposite the nipping element 14 (see FIG. 4). From this point 81, the wall curves outwardly and away from the shaft end and merges at a point 82 on the under side 86 of a disk 83 secured by screws 84 to the top of the head 65. The beveled outer edge 85 of the disk is disposed in the plane of and cooperates with a lower edge of the cover surface 35 to define the inlet to the collecting chamber 10 and through which the stream 12 of fibers is sucked into and enters through the cover opening 36. The slot 78 is relatively narrow as shown in FIGS. 3 and 5 with its outer end 87 (FIGS. 3 and 4) opening outwardly toward and disposed immediately behind the trailing side of the nipping element 14 which determines the point 88 (FIGS. 5, 7, l1 and 13) at which the fiber band is drawn away from the collecting surface 11.

The slot thus constructed defines an open space or passage through which a length 89 of the band drawn off from the collecting surface 11 behind the passing nipping element 14 may be extended from this surface straight to and into the shaft end 81 at a substantial angle relative to the plane of rotation of the drum 21. This angle which is determined by the axial spacing of the drum and the shaft end 77 and which has been found to be suitable is Within a range of 20 to 60 degrees, an angle on the order of 40 degrees as shown being preferred. The shaft end 81 serves as a guide for directing a length 91 of the advancing band into the shaft and along the axis thereof to the take-up rolls so that the desired twisting of the band will be effected by rotation of the nipping element about this axis.

In the preferred form shown herein, the nipping element 14 comprises the rounded and outer free end of a resilient arm 92 mounted cantilever fashion on the rotating head 65 to flex radially thereof and bear continuously and outwardly against the fiber band 13 with a force which is of small magnitude and, because of the light weight of the arm, is not influenced appreciably by the centrifugal force due to the high speed of the head. To these ends, the arm is formed from a flat strip of spring steel about .008 of an inch thick and of a width substantially equal to the width of the area of the collecting surface exposed to the holes 37, the strip being bent into the form and dimensioned as shown in FIGS. 5 and 6.

At the inner end, the strip is curled into an eye 93 with a laterally projecting end 94, the two being inserted, after collapsing the eye, in an outwardly opening socket 95 (FIGS. 3 and 5) of complemental cross-section with the end 94, after expansion of the eye within the socket, bearing against a trailing edge 96 and the other edge of the eye engaging the leading edge 97 of the socket. From the latter, a portion 98 of the strip is substantially flat and projects outward and radially toward the perforated wall 11 and to a substantially right angular bend 99 which stops short of the band 13 of fibers on the wall 11. Trailing this bend is a substantially straight length 101 of the strip lying alongside of and converging at a small angle toward the fiber band while terminating at active surface 88 of the nipping element 14. As shown in FIG. 5, this arm 101 extends circumferentially around the head 65 and the drum 21 in a direction opposite to the rotation of the head relative to the drum. Beyond this point, the strip is curled inwardly at 102 and away from the wall 11 through about a half revolution. The curl imparts rigidity to the free and active end of the arm and provides an inwardly rounded surface around which the fiber band forms as it is drawn inwardly away from the perforated wall.

The trailing end of the arm 92 as defined by the curl 102 is disposed opposite the outer end 87 (FIG. 5) of the leading wall of the slot 78. Thus, the fiber band, as drawn away from the perforated wall 11, passes directly into the slot and, without contact with the slot walls, is bent downwardly and pulled straight into the end of the shaft 72 around the rounded end surface 77 as shown in FIG. 4.

The spring arm 92 formed and anchored in the socket 95 as above described is stressed to swing outwardly about the point 97 (FIG. 5) as a fulcrum and urge the nipping element 14 against the passing band of fibers under a force which, combined with centrifugal force acting on the portions 101 and 102 of the spring arm, provide a very light pressure compressing the passing fiber band against the perforated drum wall 11. For a drum having a circumference of eight inches and rotating at 8,000 r.p.m. with a spring arm of the character described above, it has been found that a suitable outward static pressure of 50 to 75 grams at the active surface of the nipping element is sufficient to control the drawing of the band in the desired manner away from the wall 11.

To move the nipping element 14 relative to the fiber band built up on the perforated wall 11 and thereby release the band from the wall at an accurately controlled rate, the invention contemplates driving the head 65 and the nipping element at a speed which differs slightly, either more or less, from the speed of the drum 21 and by an amount which is determined by the twist to be imparted to the finished yarn 56. The amount of the twist is also determined by the circumference of the drum 21 and the peripheral speed of the take-up rolls 15. That is to say, with the part 91 of the traveling and released length of the band held against turning by the rolls 15, this length will be twisted one turn during one revolution of the nipping element. Assume, for example, that the circumference of the perforated wall is eight inches and that the gearing 76 is constructed to drive the head and nipping element 200 revolutions for each 199 revolutions of the drum. This means that the nipping element travels in the direction of relation of the drum 21 and will make 200 revolutions while releasing a length of eight inches of the fiber band from the collecting surface. A twist of 200/8 or 25 turns will thus be imparted to each inch of the band released by the nipping element and therefore to the yarn passing the rolls 15.

Alternatively, the head 65 supporting the nipping element 14 may be driven at a speed, for example 199 r.p.m. slower than the speed, for example 200 r.p.m. of the drum 21. Then, the nipping element would travel relative to the drum in a direction opposite the drum rotation thus necessitating reversing the direction of projection of the spring arm 92 in the opposite direction from that shown in FIG. 5. Thus, the point 88 on the nipping element from which the fiber band is released from the drum is as before located on the trailing end of the arm 92 in its rotation relative to the drum. Reference in the appended claims to the trailing side of the nipping element therefore contemplates rotation of the nipping element around the drum axis in either direction relative to the drum rotation.

It will be apparent from the foregoing that for a drum 21 of given size, the improved spinning unit may be adapted for producing yarns of different twists simply by changing the drive ratio between the fiber collecting surface 11 and the nipping element 14. Since these elements of the different spinning units along the frame are driven from a common power source, a single set of change gears 103 (FIG. 10) will suffice for all of the units. Also, it will be observed that the density of the fibers in the band 13 built up on the collecting surface 11 and therefore the size of the final yarn 56 will be determined by the rate of delivery of fibers into the collecting chamber 10 in the stream 12 and also by the speed of the drum 21. Thus, if as assumed above, the drum is rotated at 8,000 r.p.m. and the head 65 advances one revolution in 199 of the drum, the band will, after passing of the nipping element 14, be reformed on the collecting surface 11 by the fibers which are fed into the collecting chamber during the next 199 revolutions of the drum. Such positive control over the amount of the fibers forming each part of the band as it is reformed continuously contributes to the uniformity in the size of the final yarn 56 as well as the uniformity in the distribution of the twists along the yarn.

We have also discovered that the strength and the uniformity of the twist of the yarn 56 spun in accordance with the present invention as described above may be increased substantially by stretching the lengths 89, 91 of the fiber band slightly as it is being twisted between the nipping element and the take-up rolls 15. This may be accomplished by adjusting the gearing 55 so as to drive the take-up rolls 15 at a peripheral speed sufficiently greater than the speed of the nipping element 14 relative to the drum 21 to reduce the number of twists per inch of the yarn from the 25 in the example given above to 23, for example. The amount of such drafting of the band during the spinning will, of course, vary somewhat with different kinds of fibers, etc. in order to obtain a yarn of optimum quality.

Spinning yarn by the process and with the apparatus above described may be started easily by the use of a fishing tool 105 (FIG. 9) comprising a flexible rod long enough to be inserted through the outer end of the shaft 72 and reach the collecting surface 11 and having a plurality of flexible fingers 106 which, by turning of the rod while the fingers are pressed, as shown in FIG. 8, into engagement with the fiber band 13 built up as above described, becomes attached to the fibers of the band so securely that the band may be broken by retracting the tool as shown in FIG. 12. A rod having suitable resistance to torsional twisting may be a length 107 of so-called airplane cable about .034 in diameter braided from a multiplicity of strands of wire and enclosed in a plastic sheath 108. A short length of the strands at one end are exposed beyond the sheath and frayed to form the easily flexible fingers 106 which will tangle with the fibers when rotated in contact therewith. Turning of the tool is facilitated by a rod 110 attached to the other end of the cable.

In using the tool 105 to start the spinning, the drive for the shafts 27 and 72 is engaged to initiate and continue rotation of the shafts for a predetermined number of revolutions, for example 600, while the stream 12 of fibers is being supplied to the collecting chamber 10 so as to build up an annulus 109 (FIG. 13) on the wall 11. Rotation of the drum is then stopped and the frayed end of the fishing tool 105 is inserted into the outer end of the shaft 72 and pushed therethrough. Beyond the beveled end 77, the fingers 106 engage the wall 79 of the slot 78 and are guided thereby to the disk 83 and then across and beyond the surface 86 thereof and into engagement with the fibers of the annulus 109 as shown in FIG. 8 and on the trailing side of the nipping element 14. Then, by turning the rod 105, the fingers 106 become tangled with the fibers of the annulus and interlocked therewith so securely that the annulus may, by retraction of the rod and fingers, be pulled inwardly, downwardly and away from the perforated wall 11 to the position shown in FIG. 12.

With the rod stopped in this position, rotation of the drum 21 is started simultaneously with further retraction of the rod with the fibers of the annulus attached to the fingers 106. The engaged part of the annulus is drawn farther inwardly and into the slot 78. Such retraction of the rod draws a loop 111 of the band of fibers as shown in FIG. 13. Further retraction of the tool after the fibers of the annulus have come against the trailing outer edge 112 of the slot results in breaking of the annulus and drawing of the broken end portion through the beveled end 81 and into the shaft 72. Twisting of the released length of the fiber band is thus initiated so that by the time the fingers 106 of the tool have been withdrawn from this shaft, the fiber band will have been twisted enough to be gripped and manually led in between the take-up rolls 15. After a length of partially twisted yarn has passed the take-up rolls 15, this length is broken off and the advancing yarn having the desired twist is led manually around rolls 57 and the dancer roll 58, laid into the groove of the winding drum 61, and then wrapped around the core 62 to initiate or continue the formation of the package 63 as the spinning and winding continues.

Suitable means (not shown) which may take many different forms is provided for controlling the starting and stopping of the individual spinning units 16 including the drives to the shafts 27, 72. Also, a suitable device 113 (FIG. 10) engages the thread 56 before the take-up rolls 15 and operates to detect breakage of the traveling thread. Such breakage may be indicated by a signal which may be used to interrupt the drive to the spinning unit.

We claim:

1. The method of open end spinning of yarn including the steps of (a) supplying fibers detached from each other in a continuously flowing stream,

(b) directing said stream of fibers continuously into an annular collecting chamber and against an outer perforated peripheral wall thereof while the latter is rotating about a fixed axis and at a peripheral speed sufiiciently greater than the linear speed of delivery of the fibers to distribute the fibers around and against the full periphery of said wall in the form of a band,

(c) pressing a nipping element continuously and outwardly under yielding pressure against said band of fibers whereby to define a point for the inward bending and separation of the band of fibers away from said wall,

(d) rotating said nipping element around said axis in the same direction as said wall and at a speed differing slightly from the wall speed whereby to cause the element to turn relative to said wall at a speed determined by the amount of twist tobe imparted to the yarn, and

(e) drawing the band of said fibers inwardly and away from said wall at the trailing side of said nipping element in its rotation relative to said wall and then along said axis at a constant rate while holding the band against turning at point spaced along said axis and away from said nipping element whereby to effect twisting of the yarn between such point and the element.

2. The method defined in claim 1 including the step of drawing air from said chamber outwardly through the perforations in said collecting wall around. an arcuate area thereof adjacent the point of delivery of the fibers into the shoulder whereby to supplement the centrifugal force exerted on the fibers as delivered into said chamber and thereby assist in distributing the fibers around the wall to form said band with the fibers in generally parallelized relation.

3. The method as defined in claim 1 including the step of drawing the band of fibers, as separated from said surface at said nipping element, first inwardly to said axis at a substantial angle relative to the plane of said chamber and then along said axis past said holding point, the length of the band traveling from the nipping element to said axis being unsupported.

4. The method as defined in claim 1 including the step of drawing the band of fibers, as separated fromsaid surface at said nipping element, first inwardly to said axis at an angle of about forty degrees relative tothe plane of said chamber and then along the axis past said holding point.

5. The method as defined in claim 1 in which the linear speed of the twisted yarn traveling past said holding point is slightly greater than the peripheral speed of said nipping element relative to said perforated wall whereby to stretch 9 the band of fibers while the band is being twisted between said nipping element and said holding point.

6. Apparatus for open end spinning having, in combination, a rotary drum defining an annular chamber having a perforated outer wall, means for supplying a stream of detached fibers continuously into one end of said drum, means for rotating said drum about said axis at a peripheral speed many times the linear speed of said fiber stream whereby to cause the incoming fibers to be distributed around the full circumference of said wall in the form of a substantially continuous band, a nipping element within said chamber rotatable about said axis and continuously engaging saidband of fibers and urging the same against said wall at a point behind which the band of fibers may be drawn inwardly and away from said wall, means supporting said nipping element within said chamber and rotating about said axis in the same direction as but at a speed differing slightly from the speed of said wall whereby the point of inward bending of the band away from the wall moves continuously around said axis and relative to the wall, take-upmeans engaging the pulled away fibers at a point spaced along said axis from said element and drawing such fibers out of said chamber and along said axis at a rate substantially equal to the peripheral speed of said element relative to said wall while holding the fibers against turning at the point of engagement and thereby cause the length of fibers between said nipping element and take-up means to be twisted and formed into yarn.

7. Spinning apparatus as defined in claim 6 in which said stream of fibers travels into said chamber along a path extending generally parallel to but offset laterally from the drum axis so that the fibers enter said chamber adjacent said perforated wall.

8. Spinning apparatus as defined in claim 7 including means at the end of said drum defining an end wall for said chamber diverging from a central opening around said fiber stream and to the perforated area of said wall, means for drawing air at relatively high velocity into said chamber through said opening and then outwardly through the perforations of said wall and including a nozzle disposed adjacent and opening toward the outer surface of said drum over an arc of said perforations opposite said path of entry of said fiber stream.

9. Spinning apparatus as defined in claim 6 in which said perforated wall is substantially cylindrical and including means rotating with said drum and providing a generally frusto-conical surface diverging to the perforated area of said wall and defining a central opening through which said fiber stream enters near and past the inner edge of the surface, said surface serving to guide the incoming fibers to the perforated area of said rotating wall.

10. Spinning apparatus as defined in claim 6 in which said stream travels into said chamber along a path generally parallel to but offset laterally from the drum axis and including means for drawing air axially and at relatively high velocity into the end of said chamber and then outwardly through the perforations of said wall, said last means including a suction nozzle disposed adjacent and opening inwardly toward the outer surface of said drum around a substantial arc of the perforations opposite said path of entry of the fiber stream.

11. Spinning apparatus as defined in claim 6 in' which said nipping element is carried by a support disposed within and rotatable in synchronism with the drum and comprises the free end of an elongated arm composed of resiliently flexible material and mounted cantilever fashion on said support and extending circumferentially around the drum in a direction opposite the direction of rotation of the support relative to the drum, said arm being stressed to flex radially of said drum and maintain said free end in light yielding engagement with the fiber band being built up continuously around said perforated wall.

12. Spinning apparatus as defined in claim 11 in which said arm converges toward said perforated wall so as to induce all of the fibers collecting on the wall to pass between the wall and the nipping element.

13. Spinning apparatus as defined in claim 11 in which said arm is a strip of resilient material bent reversely near its free end to form the nipping element.

14. Spinning apparatus as defined in claim 11 in which the perforated area of said wall is substantially cylindrical and of a width substantially equal to the width of the active surface of said nipping element.

15. Spinning apparatus as defined in claim 11 in which said arm is a strip of resilient material bent intermediate its ends into angular form with one end anchored on said support and the other end portion bent reversely near the free end to provide a rounded surface engaging said fiber band.

16. Spinning apparatus as defined in claim 11 in which said arm is a strip of resilient metal bent reversely at one end to provide a rounded surface engaging said fiber band and bent at the opposite end to form a generally circular eye disposed within and expanded against the wall of a socket formed in said support and opening ra-: dially and outwardly to provide a slot through which said arm projects.

17. Spinning apparatus as defined in claim 16 in which the free end portion of said eye is bent laterally and abuts one edge of said slot while the arm bears against the other slot edge.

18. Apparatus for open end spinning having, in combination, a drum rotated at relatively high speed and defining an annular chamber having a perforated outer wall, mechanism for supplying detached fibers into said drum and causing the same to collect on said wall in the form .of an arcuate band, a nipping element within said chamber rotatable about the axis of said drum and engaging said band of fibers and urging the same against said wall at a point beyond which said band of fibers may be drawn inwardly and away from said wall, a support for said nipping element disposed within said drum and rotated about said axis at a speed differing slightly from the speed of said wall whereby the point of release of the fiber band moves continuously around said axis and relative to said wall, take-up means engaging the fiber band at a point spaced along said axis from said element and drawing the band out of said chamber and along said axis at a rate substantially equal to the peripheral speed of said element relative to said wall while holding the fibers against turning at the point of engagement and thereby causing the length of fibers between said nipping element and take-up means to be twisted and formed into yarn, said nipping element comprising the free end of an elongated and resiliently flexible arm mounted on said support cantilever fashion and stressed to flex radially of said drum and maintain said free end in light yielding engagement with the fiber band accumulating on said perforated wall.

19. Spinning apparatus as defined in claim 18 in which said nipping element extends from a point of anchorage on said support circumferentially around said drum in a direction opposite the rotation of the element relative to the drum.

20. Spinning apparatus as defined in claim 19 in which said arm converges toward said perforated wall so as to induce the fibers collecting on the wall to pass between the wall and the nipping element while permitting drawing of the band inwardly and away from the way on the trailing side of the nipping element.

21. Spinning apparatus as defined in claim 18 in which said support for said nipping element is fixed to a tubular shaft disposed on and extending along the axis of said drum with opposite ends disposed between said take-up means and the plane of said chamber and including means formed on and rotatable with said support and operable on a flexible tool inserted through and beyond said shaft to guide the end of the tool first along said axis and then laterally into endwise abutment with said perforated wall.

22. Spinning apparatus as defined in claim 21 in which said guiding means comprises a wall formed on said support and extending from one side of the inner wall of said shaft along said axis toward said plane and laterally across the axis and into such plane for endwise abutment with a band of fibers collected on and extending around said perforated wall.

23. Spinning apparatus as defined in claim 21 in which said flexible tool is formed at its leading end with a plurality of fingers flaring away from each other and adapted, when the tool is turned with the fingers engaging a band of fibers on said wall to become tangled with such fibers and, upon withdrawal of the tool to break said band away from said wall and permit withdrawal of the band through said shaft during subsequent rotation of said drum and said support.

24. The method of starting the spinning of yarn by the method defined in claim 1 including the steps of (a) feeding fibers into said collecting chamber while rotating the latter,

(b) interrupting said rotation after a limited number of revolutions to form an annulus of the fibers around the interior of said wall,

(c) inserting along said axis reversely of the yarn travel an elongated laterally flexible rod having a plurality of flaring fingers at its end,

((1) guiding such end into engagement with said annulus adjacent said nipping element while twisting the rod to entangle said fingers with the fibers of the annulus,

(e) retracting the rod a short distance to draw a length thereof adjacent nipping element away from said wall, and,

(f) while continuing the withdrawal of the rod, re-

suming the turning of said wall and the feeding of fibers to said chamber to initiate said spinning of yarn.

References Cited UNITED STATES PATENTS 3,163,976 1/1965 Juillard 57-58.89 3,295,307 1/1967 Kyame et a1. 5758.89

JOHN PETRAKES, Primary Examiner 

